U.S. patent number 11,247,347 [Application Number 16/799,600] was granted by the patent office on 2022-02-15 for linkage system for prehending objects using impactive forces.
This patent grant is currently assigned to Amazon Technologies, Inc.. The grantee listed for this patent is Amazon Technologies, Inc.. Invention is credited to Erica Aduh, Gregory Coleman, Timothy G. Dietz, Jonas Eichenberger, Dominique Ernst, Margaret Jean Williams George, Leonard Thomas Lilliston, III, Beth A. Marcus, Mathias Moser, Manikantan Nambi, Ueli Schlaepfer, Parris S. Wellman.
United States Patent |
11,247,347 |
Wellman , et al. |
February 15, 2022 |
Linkage system for prehending objects using impactive forces
Abstract
Aspects described herein include an end effector capable of
prehending items using impactive and astrictive forces. The end
effector includes an interface system having a deformable mounting
plate and a pliable body member attached to the mounting plate. The
end effector further includes a linkage system between a plurality
of actuators and the interface system. The linkage system connects
to lateral portions of the mounting plate.
Inventors: |
Wellman; Parris S. (Reading,
MA), Marcus; Beth A. (Bedford, MA), Coleman; Gregory
(Somerville, MA), Nambi; Manikantan (Malden, MA), Aduh;
Erica (Cambridge, MA), Dietz; Timothy G. (Reading,
MA), Lilliston, III; Leonard Thomas (Sudbury, MA),
George; Margaret Jean Williams (Cambridge, MA),
Eichenberger; Jonas (Zurich, CH), Moser; Mathias
(Zurich, CH), Ernst; Dominique (Zurich,
CH), Schlaepfer; Ueli (Affoltern am Albis,
CH) |
Applicant: |
Name |
City |
State |
Country |
Type |
Amazon Technologies, Inc. |
Seattle |
WA |
US |
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Assignee: |
Amazon Technologies, Inc.
(Seattle, WA)
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Family
ID: |
1000006117714 |
Appl.
No.: |
16/799,600 |
Filed: |
February 24, 2020 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20210086372 A1 |
Mar 25, 2021 |
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Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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62952999 |
Dec 23, 2019 |
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62903500 |
Sep 20, 2019 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B25J
9/123 (20130101); B25J 15/0683 (20130101); B25J
9/1612 (20130101); B25J 9/0015 (20130101) |
Current International
Class: |
B25J
15/00 (20060101); B25J 15/06 (20060101); B25J
9/00 (20060101); B25J 9/16 (20060101); B25J
9/12 (20060101) |
Field of
Search: |
;294/183,185 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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1204140 |
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Oct 1965 |
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102010043036 |
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May 2012 |
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102013208778 |
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Nov 2014 |
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DE |
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102015107394 |
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Nov 2016 |
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102015210316 |
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Dec 2016 |
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DE |
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102016115102 |
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Feb 2018 |
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DE |
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102016011618 |
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Mar 2018 |
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DE |
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Other References
US. Appl. No. 16/899,885, "Varying Strength Interface System for
Robotic End-Effector", filed Jun. 12, 2020. cited by applicant
.
German Office Action for Application No. 102020005752.7 dated Jun.
23, 2021. cited by applicant .
Great Britain Intellectual Property Office Search Report for
Application No. GB2014553.8 dated Mar. 17, 2021. cited by applicant
.
German Patent and Trademark Office, Examination Report for
Application 112019003240.4, dated Sep. 28, 2021. cited by
applicant.
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Primary Examiner: Chin; Paul T
Attorney, Agent or Firm: Patterson + Sheridan, LLP
Parent Case Text
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is related to U.S. patent application Ser. No.
16/018,748, filed Jun. 26, 2018. This application also claims
domestic benefit of U.S. provisional patent application Ser. Nos.
62/903,500 filed Sep. 20, 2019 and 62/952,999 filed Dec. 23, 2019.
Each of the aforementioned patent applications is herein
incorporated by reference in its entirety.
Claims
What is claimed is:
1. An end effector capable of prehending items using impactive and
astrictive forces, the end effector comprising: a central
structural member arranged around a central axis of the end
effector; a plurality of actuators; an interface system comprising:
a deformable mounting plate; and a pliable body member attached to
the mounting plate, the pliable body member having, at a distal
end, a sealing surface configured to seal with items brought into
proximity with the end effector, the pliable body member at least
partially defining an inner recess; a vacuum port in fluid
communication with the inner recess and arranged around the central
axis; and a linkage system between the plurality of actuators and
the interface system, the linkage system comprising, for each
actuator of the plurality of actuators: a first link connected
with: an end of the actuator at a first joint, the first joint at a
first radial distance from the central axis; and the central
structural member via a second joint, the second joint at a second
radial distance less than the first radial distance; and a second
link connected with: the first link at a third joint, the third
joint at a third radial distance greater than the first radial
distance; and a lateral portion of the mounting plate at a fourth
joint, the fourth joint at a fourth radial distance greater than
the third radial distance.
2. The end effector of claim 1, wherein the plurality of actuators
comprises: a first pair of opposing linear actuators within a first
plane; and a second pair of opposing linear actuators within a
second plane orthogonal to the first plane.
3. The end effector of claim 1, wherein at least one component of
the linkage system is rotatable about a rotation axis to cause the
mounting plate to rotate about the central axis.
4. The end effector of claim 3, wherein the first link comprises: a
first link component; and a second link component rotatable
relative to the first link component.
5. The end effector of claim 3, wherein the linkage system further
comprises, for each actuator of the plurality of actuators: an
intermediate member connected with the first link at the second
joint, wherein the intermediate member is rotatable relative to the
central structural member.
6. A method of prehending an item using an end effector, the method
comprising: bringing the item into proximity of a sealing surface
at a distal end of a pliable body member; applying a suction force
to an inner recess defined within the pliable body member, thereby
causing the end effector to apply an astrictive force to the item;
and applying, using a plurality of actuators connected with lateral
portions of a deformable plate through a linkage system, at least a
first force to deform the deformable plate and cause the end
effector to apply an impactive force to the item.
7. The method of claim 6, wherein the end effector applies the
impactive force to the item prior to applying the suction force to
the inner recess.
8. The method of claim 6, further comprising: prior to contacting
the item with the sealing surface, applying at least a second force
using the plurality of actuators to deform the deformable plate and
alter a geometry of the sealing surface.
9. The method of claim 6, wherein at least one component of the
linkage system is rotatable about a rotation axis to cause the
deformable plate to rotate about a central axis of the end
effector, and wherein contacting the item with the sealing surface
causes the at least one component to rotate such the sealing
surface is more closely aligned with a geometry of the item.
10. The method of claim 6, wherein the plurality of actuators
comprises linear actuators, wherein applying the first force
comprises extending a first linear actuator of the plurality of
actuators to apply the first force to a first joint of a first
link, wherein applying the first force causes the first link to
rotate about a second joint that connects the linkage system with a
central structural member of the end effector, wherein rotating the
first link about the second joint causes a second force to be
applied to a third joint connecting the first link with a second
link, and wherein applying the second force to the third joint
causes a third force to be applied to a fourth joint connecting the
second link with a first lateral portion of the lateral
portions.
11. The method of claim 10, wherein the first joint is at a first
radial distance from a central axis of the end effector, wherein
the second joint is at a second radial distance less than the first
radial distance, wherein the third joint is at a third radial
distance greater than the first radial distance, and wherein the
fourth joint is at a fourth radial distance greater than the third
radial distance.
12. An end effector for prehending items, the end effector
comprising: a plurality of actuators; an interface system
comprising a deformable plate; and a linkage system between the
plurality of actuators and the interface system, the linkage system
comprising, for each actuator of the plurality of actuators: a
first link connected with: an end of the actuator at a first joint,
the first joint at a first radial distance from a central axis of
the end effector; and a central structural member via a second
joint, the second joint at a second radial distance less than the
first radial distance; and a second link connected with: the first
link at a third joint, the third joint at a third radial distance
greater than the first radial distance; and a lateral portion of
the deformable plate at a fourth joint, the fourth joint at a
fourth radial distance greater than the third radial distance,
wherein at least one component of the linkage system is rotatable
about a rotation axis to cause the deformable plate to rotate about
the central axis.
13. The end effector of claim 12, wherein the plurality of
actuators comprises linear actuators, wherein extending at least
two opposing linear actuators of the plurality of actuators causes
the deformable plate to deform, and wherein the deformable plate,
when deformed, causes the end effector to apply an impactive force
to an item.
14. The end effector of claim 13, wherein the interface system
further comprises: a pliable body member attached to the deformable
plate and having a sealing surface at its distal end configured to
seal with items brought into proximity with the end effector, the
pliable body member at least partially defining an inner recess,
and wherein the end effector further comprises a vacuum port in
fluid communication with the inner recess.
15. The end effector of claim 14, wherein the vacuum port is
arranged around the central axis.
16. The end effector of claim 12, wherein the linkage system
further comprises, for each actuator of the plurality of actuators:
an intermediate member connected with: the first link at the second
joint; an exterior of the actuator via a fifth joint, the fifth
joint at a fifth radial distance greater than the second radial
distance; and the central structural member via a sixth joint,
wherein the rotation axis is the rotation axis of the sixth
joint.
17. The end effector of claim 16, wherein the fifth joint is at a
sleeve arranged around the actuator, the sleeve configured to
rotate about the actuator.
18. The end effector of claim 16, wherein the rotation axis of the
sixth joint is substantially parallel to the central axis of the
end effector.
19. The end effector of claim 16, wherein each intermediate member
defines an opening through which the respective actuator passes,
and wherein the opening limits a range of motion of the respective
actuator when the intermediate member is rotated about the rotation
axis.
20. The end effector of claim 16, wherein the central structural
member comprises: one or more stop features that limit a range of
rotation of the intermediate member about the rotation axis.
21. The end effector of claim 12, wherein the first link comprises:
a first link component connected with: the end of the actuator at
the first joint; and the central structural member at the second
joint; and a second link component connected with: the second link
at the third joint; and the first link component at a fourth joint,
wherein the rotation axis is the rotation axis of the fourth
joint.
22. The end effector of claim 12, wherein the central structural
member is included in a structural assembly further comprising: a
second central structural member spaced apart from, and rigidly
connected with, the central structural member, wherein each
actuator of the plurality of actuators is connected with the second
structural member at a respective second end that is opposite the
end connected with the first link; and a third central structural
member connected with one of the central structural member and the
second central structural member, wherein the structural assembly
is rotatable about a second rotation axis extending through the
third central structural member.
23. The end effector of claim 22, further comprising: a first
sprocket connected with a motor; and a second sprocket connected
with the first sprocket via a toothed belt, and with the third
central structural member.
24. The end effector of claim 23, wherein an opening extends
through the second sprocket, wherein the interface system further
comprises: a pliable body member attached to the deformable plate
and having a sealing surface at its distal end configured to seal
with items brought into proximity with the end effector, the
pliable body member at least partially defining an inner recess,
and wherein the end effector further comprises a vacuum port in
fluid communication with the inner recess through the opening and
through the third central structural member.
Description
BACKGROUND
The present disclosure relates to prehending items using an end
effector, and more specifically, to implementations of an end
effector having a linkage system capable of applying impactive
force to the items.
BRIEF DESCRIPTION OF DRAWINGS
Various embodiments in accordance with the present disclosure will
be described with reference to the drawings, where like
designations denote like elements.
FIGS. 1A and 1B are diagrams of an exemplary end effector,
according to various embodiments.
FIGS. 2A and 2B illustrate moving an item using an end effector,
according to various embodiments.
FIG. 3 illustrates an exemplary method of prehending items using
impactive and astrictive forces, according to various
embodiments.
FIG. 4 illustrates an exemplary method of operating a linkage
system of an end effector, according to various embodiments.
FIGS. 5A-5E are views of an end effector having an exemplary
implementation of a linkage system, according to various
embodiments.
FIGS. 6A and 6B illustrate an exemplary sequence of prehending an
item using an end effector, according to various embodiments.
FIGS. 7A-7C are bottom views illustrating altering a geometry of a
sealing surface by deforming a deformable plate, according to
various embodiments.
FIGS. 8A-8C are views of an end effector having another exemplary
implementation of a linkage system, according to various
embodiments.
FIGS. 9A-9D are views of an exemplary end effector having a
rotatable structural assembly, according to various
embodiments.
DETAILED DESCRIPTION
While conventional suction-based end effectors may be effective at
moving items having relatively large planar surfaces, the ability
to move items without suctioning a single planar surface (e.g., an
item lacking a planar surface, an item having a planar surface that
is inaccessible in a particular orientation of the item relative to
the end effector, and so forth) remains a technical challenge.
Further, suctioning may be difficult or entirely unsuitable for
certain types of items, such as those having porous surfaces (e.g.,
a wire or woven basket) causing suction force to be lost.
According to embodiments described herein, an end effector
comprises an interface system having a deformable plate, and a
linkage system connected with lateral portions of the deformable
plate, such that applying force(s) to the linkage system causes the
deformable plate to deform. In some cases, deforming the deformable
plate causes the end effector to apply an impactive force to an
item.
In some embodiments, the interface system further comprises a
pliable body member with a sealing surface. The pliable body member
at least partly defines an inner recess in fluid communication with
a vacuum port. In some cases, deforming the deformable plate alters
a geometry of the sealing surface, such that the sealing surface is
more closely aligned with a geometry of the item to form an
improved seal with the item. Further, at least one component of the
linkage system may be rotatable to allow the deformable plate to
rotate relative to other components of the end effector, such that
the sealing surface is more closely aligned with the geometry of
the item. In some embodiments, the end effector prehends the item
using both impactive (e.g., gripping) and astrictive (e.g.,
suctioning) forces.
Using the various implementations of the end effector enables items
with complex and/or irregular shapes to be manipulated at greater
velocities and/or accelerations without a loss of suction and/or
without damaging the items. For example, altering the geometry of
the sealing surface may allow a small item to be selectively picked
from among multiple small items. Further, the linkage system may be
located close to the deformable plate and/or the pliable body
member, which reduces the overall size of the end effector and
permits the end effector to reach items having a reduced or
restricted accessibility. In one example, an item may be located in
a corner of a tote, such that the walls of the tote may interfere
with the end effector as it approaches the item. In another
example, an item may have a difficult orientation, such as a book
lying flat on the bottom of a tote where the spine of the book is
the target contact region for the end effector.
FIGS. 1A, 1B are diagrams 100, 120 of an exemplary end effector
105, according to various embodiments. More specifically, the
diagram 100 represents an exterior view of the end effector 105,
and the diagram 120 represents a cross-sectional view of the end
effector 105. The end effector 105 may be used within an industrial
automation system or any alternate environment suitable for
prehending and moving items.
The end effector 105 comprises an interface system 110 attached to
a manifold 115. The interface system 110 comprises a pliable body
member 125 (or "body member") made of any pliable material(s)
suitable for forming a seal with a contacting item and maintaining
a vacuum. In some embodiments, the pliable body member 125
comprises a suitable closed cell or open cell foam. Some
non-limiting examples of pliable materials include polymeric foams
such as nitrile rubber foam, polyurethane foam, silicon foam,
polychloroprene foam (neoprene), and so forth. Other non-limiting
examples of pliable materials include elastomeric materials such as
latex, rubber, and silicone.
The pliable body member 125 comprises an inner surface 130 defining
an inner recess 135 (also referred to as a "region", a "central
region", or a "vacuum region"). The pliable body member 125 may be
monolithic or may comprise a plurality of sections that are
dimensioned and arranged in such a manner that a vacuum may be
formed and maintained between the pliable body member 125 and the
item to be suctioned. The pliable body member 125 may have any
suitable shape that defines the inner recess 135, such as an
annular disk, a bellows suction cup, and so forth.
Although shown as being a continuous shape, in some cases the
pliable body member 125 may define one or more gaps that
accommodate the movement of material of the pliable body member 125
during deformation thereof. For example, the gaps may extend
radially from a center of the pliable body member 125, and in some
cases may be arranged relative to known locations where force is
applied to deform the interface system 110. The one or more gaps
are dimensioned such that only a minor amount of suction force is
lost when the pliable body member 125 is in an undeformed state.
Further, the one or more gaps may be partially or fully closed as
material from the pliable body member 125 moves during deformation.
In some cases, the pliable body member 125 may define one or more
perforations that accommodate the movement of material of the
pliable body member 125 during deformation thereof.
The pliable body member 125 may be configured to entirely
circumscribe the inner recess 135. In some embodiments, when the
pliable body member 125 is in an undeformed state, the inner
surface 130 and/or the inner recess 135 have elliptical shapes,
such as an ellipse or a circle. When viewed from a top view, the
manifold 115 and the interface system 110 may have elliptical
shapes that are concentric and not coextensive. However, other
suitable shapes, sizes, coextensive, and/or non-concentric
arrangements of the manifold 115 and the interface system 110 are
also possible.
The pliable body member 125 further comprises a sealing surface 140
at a distal end of the pliable body member 125. The distal end of
the pliable body member 125, at which items may be contacted and/or
suctioned to the end effector 105, may correspond to a distal end
of the end effector 105. The sealing surface 140 defines an opening
145 to the inner recess 135. In some embodiments, bringing an item
into proximity with the sealing surface 140 causes the sealing
surface 140 to conform to a contour of the item and thereby seals
the inner recess 135 from ambient. In some cases, bringing the item
into proximity with the sealing surface 140 comprises contacting
the item to the sealing surface 140. In other cases, bringing the
item into proximity with the sealing surface 140 comprises bringing
the item close to (although not contacting) the sealing surface
140. As discussed herein, forming a seal with an item (e.g.,
contacting the item to the sealing surface 140) does not strictly
require that all suction force be maintained. It is contemplated
that a minor amount of suction force may be lost while the end
effector 105 suctions the item, so long as the maintained suction
force is sufficiently large to withstand inertial forces that are
expected when moving the item.
In some embodiments, the interface system 110 further comprises a
mounting plate 170 to which the pliable body member 125 is
attached. The mounting plate 170 may have any suitable
implementation for pivoting and/or deforming responsive to applied
forces. For example, the mounting plate 170 may be formed as a
pivotable plate having one or more pivot axes. Some exemplary
implementations of the mounting plate 170 are described in U.S.
patent application Ser. No. 16/018,748, which is herein
incorporated by reference in its entirety.
In some embodiments, the mounting plate 170 pivots and/or deforms
to further control a shape and/or sizing of the suction area
presented by the end effector 105. In some embodiments, the
mounting plate 170 pivots and/or deforms such that the end effector
105 provides impactive forces (e.g., gripping) in addition to the
astrictive forces (e.g., suction) provided by the vacuum.
In some embodiments, the mounting plate 170 has a greater rigidity
than the pliable body member 125, and may be formed of different
material(s) and/or differently dimensioned. For example, the
greater rigidity of the mounting plate 170 may allow one or more
actuators 160 to, via a linkage system 175, deform the pliable body
member 125 without causing substantial wear or damage thereto. In
one embodiment, the mounting plate 170 comprises a rubber material,
but other types of pliable materials are also possible. In some
alternate embodiments, the mounting plate 170 may be rigid, such
that application of the vacuum and/or the compressed gas does not
cause the mounting plate 170 to deform.
In some alternate implementations, the one or more actuators 160
may contact and deform the pliable body member 125 without an
intermediate mounting plate 170.
The pliable body member 125 may be attached to the mounting plate
170 using any suitable techniques. In some embodiments, the pliable
body member 125 is attached to the mounting plate 170 using one or
more of an adhesive layer, a glue, and a fabric. In some
embodiments, the pliable body member 125 is attached to a flexible
backing plate, and the flexible backing plate is then attached to
the mounting plate 170 (e.g., via adhesive layer, glue, and/or
fabric).
In some embodiments, the mounting plate 170 defines one or more
openings extending therethrough. For example, the mounting plate
170 may define a first opening through which the vacuum port 150 is
in fluid communication with the inner recess 135. As shown in the
diagram 120, the first opening may be centrally located (e.g.,
aligned with a central axis of the end effector 105). However,
other implementations of the mounting plate 170 (e.g., a different
number of openings) are also contemplated.
In some embodiments, the force applied by the one or more actuators
160 via the linkage system 175 to the mounting plate 170 causes the
mounting plate 170 to move (for example, to pivot and/or deform).
In some embodiments, the applied force deforms the pliable body
member 125, which alters a geometry of the sealing surface 140. In
some embodiments, the applied force alters a relative orientation
of different sealing surfaces 140 of the interface system 110.
The one or more actuators 160 may be of any suitable type(s). For
example, the one or more actuators 160 may be actuatable according
to any suitable means, such as pneumatic, hydraulic, mechanical,
motorized, and so forth. Further, the one or more actuators 160 may
comprise active and/or passive actuators. Some non-limiting
examples of the one or more actuators 160 include linear actuators
and rotary actuators. In one embodiment, the one or more actuators
160 comprise one or more linear actuators attached to the interface
system 110, and deforming the interface system 110 comprises
increasing a length of the one or more linear actuators.
In some embodiments, the pliable body member 125 in an undeformed
state has a surface 165 defined within a plane at a proximal end
opposite the distal end. Stated another way, a proximal surface of
the pliable body member 125 may be within a single plane in the
undeformed state, regardless of the overall shape or dimensioning
of the pliable body member 125. Conventional implementations of the
pliable body member 125 (e.g., a foam suction cup) may be
configured to maintain the surface 165 within the plane during
operation (e.g., rigidly attached and not permitted to deform),
which limits the ability of the foam suction cup to suction to
irregular, complex, and/or heavy items. In such a case, the
performance of the conventional foam suction cup to prehend items
is based solely on the compliance of the foam.
In some embodiments, the one or more actuators 160 may be used to
apply force to the pliable body member 125 at the surface 165 via
the linkage system 175 and the mounting plate 170. In this way, one
or more degrees of freedom are provided to manipulate the pliable
body member 125, which permits the pliable body member 125 to be
dynamically shaped to more closely match a surface geometry of an
item to be suctioned. This increases the compatibility of the
pliable body member 125 with different types of items having
irregular or complex geometries. This also increases the quality of
the seal formed with a suctioned item, allowing heavier items to be
moved and/or the items to be moved more rapidly.
The linkage system 175 may have any suitable implementation for
transferring forces provided by the one or more actuators 160 to
the pliable body member 125. The links of the linkage system 175
are formed of material(s) having suitable strength for transferring
the forces from the one or more actuators 160 to deform the
mounting plate 170 and the pliable body member 125. For example,
the links may be formed of metals such as stainless steel,
composite or reinforced plastics, ceramics, and so forth. In some
embodiments, the linkage system 175 connects to the interface
system 110 at lateral portions of the mounting plate 170.
The linkage system 175 defines a plurality of joints at which the
links are connected. In some embodiments, the joints comprise
pivots that permit relative rotary motion of connected links.
However, a linkage system 175 comprising other type(s) of joints
such as sliders are also contemplated. In some embodiments, one or
more links of the linkage system 175 are connected with static
structural member(s) of the end effector 105 and permitted to
rotate relative thereto.
As discussed above, deforming the mounting plate 170 alters a
geometry of the sealing surface 140 of the pliable body member 125,
which enables an improved seal to be formed with an item. In some
embodiments, the links of the linkage system 175 are dimensioned
and the joints arranged such that application of force(s) by the
one or more actuators 160 cause the pliable body member 125 to
deform to an extent that the linkage system 175 provides an
impactive force (e.g., gripping) to an item through the pliable
body member 125. Thus, the end effector 105 is capable of
prehending items using impactive and astrictive (e.g., suction)
forces.
In some embodiments, at least one component of the linkage system
175 may be rotatable, which allows the mounting plate 170 and the
pliable body member 125 to rotate relative to other components of
the end effector 105. In this way, the end effector 105 may be
capable of self-aligning with an item, which allows the sealing
surface 140 to more closely aligned with the geometry of the
item.
The manifold 115 may represent a continuously rigid portion of the
end effector 105, and may be used to interface with other
components of the industrial automation system. For example, one or
more mechanical arms for spatially manipulating the end effector
105 (e.g., displacing and/or rotating) may be attached to the
manifold 115. In another example, the manifold 115 may provide
points of attachment to the end effector 105, e.g., such as
attaching hoses to the vacuum port 150 and the compressed gas port
180 and/or attaching a cable, hose, etc. to the signaling port
155.
The manifold 115 may be formed of any suitable material(s), which
may include relatively inelastic material(s) such as plastics or
metals. However, in some cases, the manifold 115 may be formed of
elastic material(s) and dimensioned to provide a greater rigidity
than the pliable body member 125 in the first structural state. In
one non-limiting example, the manifold 115 may be formed of a same
elastomeric material as the pliable body member 125, but has a much
greater thickness than walls of the pliable body member 125. In
some cases, the manifold 115 formed of elastic material(s) may be
deformable or selectively deformable.
The manifold 115 and the interface system 110 may be connected
through any suitable means. In some embodiments, the manifold 115
and the interface system 110 are removably connected using threaded
fasteners such as screws or bolts. In other embodiments, the
manifold 115 and the interface system 110 are integrally
formed.
The end effector 105 comprises a plurality of ports. A vacuum port
150 is in fluid communication with the inner recess 135 and is
configured to apply suction force to the inner recess 135 (e.g.,
when sealed by the sealing surface 140). A signaling port 155 is in
communication with one or more actuators 160, and control signals
communicated via the signaling port 155 cause the one or more
actuators 160 to selectively apply a force to, or otherwise cause a
compliant interaction with, the interface system 110 via the
linkage system 175. Depending on the configuration of the one or
more actuators 160 and the linkage system 175, the applied force
deforms the interface system 110 according to one or more degrees
of freedom.
FIGS. 2A, 2B illustrate moving an item using an end effector,
according to various embodiments. The features illustrated in
diagrams 200, 245 may be used in conjunction with other
embodiments, such as the end effector 105 of FIGS. 1A and 1B.
The diagram 200 comprises a controller 205 that is configured to
interface with the end effector 105 through at least the vacuum
port 150 and the one or more actuators 160 via the signaling port
155. In some embodiments, the controller 205 is further configured
to interface with the end effector 105 through one or more
actuators 235 connected thereto. The one or more actuators 235 may
have any suitable form, and may control the end effector 105
according to one or more degrees of freedom. For example, the one
or more actuators 235 may be configured to translate and/or rotate
the end effector 105. Some non-limiting examples of the one or more
actuators 235 comprise articulating and/or telescoping robotic
arms, which may attach to a proximal end of the end effector
105.
The controller 205 comprises one or more computer processors 206
and a memory 208. The one or more computer processors 206 represent
any number of processing elements that each can include any number
of processing cores. Some non-limiting examples of the one or more
computer processors 206 include a microprocessor, a digital signal
processor (DSP), an application-specific integrated chip (ASIC),
and a field programmable gate array (FPGA), or combinations
thereof. The memory 208 may comprise volatile memory elements (such
as random access memory), non-volatile memory elements (such as
solid-state, magnetic, optical, or Flash-based storage), and
combinations thereof. Moreover, the memory 208 may be distributed
across different mediums (e.g., network storage or external hard
drives).
The memory 208 may comprise a plurality of "modules" for performing
various functions described herein. In one embodiment, each module
includes program code that is executable by one or more of the
computer processors 206. However, other embodiments may include
modules that are partially or fully implemented in hardware (i.e.,
circuitry) or firmware of the controller 205. As shown, the memory
208 comprises an image processing module 213 configured to perform
image processing on imagery 218 received from one or more visual
sensors 216 in the environment. The imagery 218 may have any
suitable form, such as one or more still images or video.
In some embodiments, the image processing module 116 is configured
to perform feature extraction and/or image segmentation of the
imagery 218, although any other suitable techniques are also
contemplated. The image processing performed on the imagery 218 may
be used to locate and/or identify the item 215, and/or to determine
a positioning and/or orientation of the end effector 105 relative
to the item 215. In some embodiments, the memory 208 comprises item
information 212 associated with the different items in the
environment. Visual characteristics included in the item
information 212 may be used by the image processing module 116 to
identify the item 215 and/or identify an orientation of the item
215 (e.g., a comparison of the imagery 218 with the item
information 212).
In some embodiments, the image processing module 213 is further
configured to identify a target contact region 214 of the item 215.
The target contact region 214 represents a region of the item 215
that is estimated to provide a relatively good seal with the
interface system of the end effector 105. The target contact region
214 may be determined based on a current orientation of the item
215, and may be determined based on the assumption that the item
215 will not be displaced and/or rotated prior to the end effector
105 contacting the item 215. The image processing module 213 may
comprise one or more predefined rules for determining the target
contact region 214. For example, a first rule may specify that
planar surfaces are preferred for the target contact region 214
over rounded surfaces or corners, a second rule may specify that
larger surfaces are preferred to smaller surfaces, and a third rule
may specify that a corner having a linear (or other elongated)
intersection is preferred to a corner having a point intersection.
The one or more predefined rules may be based on properties of the
end effector 105 (e.g., values or ranges of size, shape, vacuum
force, etc.), which may reflect deformation of the interface system
by the one or more actuators 160. The one or more predefined rules
may also be prioritized relative to each other.
For example, assume that the item 215 has a rectangular shape, with
relatively large planar surfaces (e.g., larger than an inner
diameter of the inner recess of the end effector 105 in an
undeformed state) on two sides, and relatively small planar
surfaces (e.g., smaller than the inner diameter) on the other four
sides. However, assume further that the large planar surfaces of
the item 215 are partially or completely inaccessible by the end
effector 105 in a current orientation of the item 215 (e.g., the
item 215 is obscured by other items, resting against a surface such
as a sidewall or floor, etc.). As it is not feasible to contact
only a large planar surface in the current orientation of the item
215, the image processing module 213 may select a "next-best"
target contact region, such as an elongated intersection of two
sides as specified by the example third rule above.
In conjunction with identifying the target contact region 214, the
image processing module 213 may determine a geometry of the target
contact region 214. Based on the geometry of the target contact
region 214, the controller 205 may send control signals to the one
or more actuators 160 to deform the interface system 110 (e.g.,
pre-shaping the sealing surface at the distal end of the end
effector 105). The controller 205 may additionally or alternately
send control signals to the one or more actuators 235 to reorient
the interface system relative to the item 215 prior to contacting
the item 215.
In some embodiments, the controller 205 is configured to transmit
control signals to the one or more actuators 235 to provide the end
effector 105 with a desired positioning and/or orientation for
contacting and/or handling the item 215. In the diagram 200, the
end effector 105 has been brought into contact with the item 215
resting on a surface 220. In some alternate embodiments, the end
effector 105 and/or the item 215 may be manually moved to provide
the contacting relationship, and/or to displace the end effector
105 and the suctioned item 215 to the predefined location. For
example, the end effector 105 may include a handle allowing a user
to rotate and/or displace the end effector 105.
In some embodiments, the controller 205 is configured to transmit
control signals to a vacuum source 230 to selectively apply a
vacuum to the inner recess of the end effector 105. The vacuum
source 230 may have any suitable implementation, such as a vacuum
pump connected to the vacuum port 150 via a flexible hose. Applying
the vacuum to the inner recess operates to apply an astrictive
force to the item 215, thereby suctioning the item 215 to the end
effector 105. In some embodiments, the controller 205 transmits
control signals to the one or more actuators 160 to apply an
impactive force to the item 215 (e.g., grasping) via the linkage
system 175. Applying the impactive force may be independent of
applying an astrictive force, or the two may be used in
combination. Further, applying the impactive force and the
astrictive force may any suitable sequencing. In some embodiments,
when the item 215 has been moved to the predefined location, the
controller 205 transmits control signals to the one or more
actuators 160 and/or the vacuum source 230 to release the grasp
and/or the suction on the item 215.
The controller 205 may further transmit control signals to the one
or more actuators 235 to displace the end effector 105 and the
now-suctioned item 215 to a predefined location, which in some
cases may be specified by destination information 210 included in
the memory 208 and associated with the item 215. The destination
information 210 may have any suitable form, such as a destination
within the warehouse (e.g., a particular container 250 or a
particular environment location), a destination external to the
warehouse (e.g., a portion of a destination mailing address or a
particular vehicle for external transport), and so forth. In some
embodiments, the controller 205 acquires the destination
information 210 from one or more computing devices that are
networked with the controller 205.
FIG. 3 illustrates an exemplary method 300 of prehending items
using impactive and astrictive forces, according to various
embodiments. The method 300 may be used in conjunction with other
embodiments, such as using any implementation of an end effector
described herein.
The method 300 begins at block 305, where a force is applied, using
a plurality of actuators connected with lateral portions of a
deformable plate through a linkage system, to deform the deformable
plate and alter a geometry of a sealing surface at a distal end of
a pliable body member. In some embodiments, the pliable body member
may be dynamically shaped to more closely match a surface geometry
of an item to be suctioned by the end effector.
At block 315, an item is contacted with the sealing surface. At
block 325, the deformable plate is rotated about a central axis of
the end effector. In some embodiments, at least one component of
the linkage system is rotatable about a rotation axis to cause the
deformable plate to rotate about the central axis. In this way, the
end effector may be capable of self-aligning with the item, which
allows the sealing surface to be more closely aligned with the
geometry of the item.
At block 335, a suction force is applied to an inner recess defined
within the pliable body member. In some embodiments, the suction
force is applied after contacting the item with the sealing
surface. In other embodiments, the suction force is applied prior
to contacting the item with the sealing surface, which in some
cases may further alter the geometry of the sealing surface. At
block 345, an astrictive force is applied to the item.
At block 355, a force is applied, using the plurality of actuators,
to deform the deformable plate. At block 365, an impactive force is
applied to the item through the linkage system. The method 300 ends
following completion of block 365.
FIG. 4 illustrates an exemplary method 400 of operating a linkage
system of an end effector, according to various embodiments. The
method 400 may be used in conjunction with other embodiments, such
as using any implementation of an end effector described herein.
The method 400 may also represent one example implementation of the
blocks 305, 355 of FIG. 3 discussed above.
At block 405, a linear actuator is extended. At block 415, a first
force is applied to a first joint of a first link. In some
embodiments, the first joint is at a first radial distance from a
central axis of the end effector. At block 425, the first link is
rotated about a second joint that connects the linkage system with
a central structural member of the end effector. In some
embodiments, the second joint is at a second radial distance less
than the first radial distance.
At block 435, a second force is applied to a third joint connecting
the first link with a second link. In some embodiments, the third
joint is at a third radial distance greater than the first radial
distance. At block 445, a third force is applied to a fourth joint
connecting the second link with a lateral portion of a deformable
plate. In some embodiments, the fourth joint is at a fourth radial
distance greater than the third radial distance. The method 400
ends following completion of block 445.
FIGS. 5A-5E are views of an end effector having an exemplary
implementation of the linkage system 175, according to various
embodiments. The features illustrated in diagrams 500, 515, 545,
570, 575 may be used in conjunction with other embodiments
discussed herein.
Diagram 500 of FIG. 5A is an isometric view of the end effector,
which comprises the linkage system 175 that connects a plurality of
linear actuators 510-1, 510-2, 510-3, 510-4 with the interface
system 110. The end effector further comprises a central structural
member 505, which connects with the linkage system 175 via at least
one joint. In some embodiments, at least one component of the
linkage system 175 is rotatable about a rotation axis, which causes
the mounting plate 170 to rotate about the central axis C
(illustrated in FIGS. 5B, 5C) of the end effector. In some cases,
the rotation of the mounting plate 170 also occurs within the plane
of the mounting plate 170.
The end effector further comprises a second central structural
member 506 that is spaced apart from, and rigidly connected with,
the central structural member 505. A rod 507 extends between
lateral portions of the central structural member 505 and of the
second central structural member 506. Although not shown in the
diagram 500, one or more other rods may extend between the central
structural member 505 and of the second central structural member
506. The rod 507 has a longitudinal axis parallel to the central
axis C. The rod 507 may be secured to the central structural member
505 and to the second central structural member 506 using, e.g.,
threaded fasteners.
An opening 508 extends through the plane of the second central
structural member 506, and is dimensioned and arranged such that
each of the linear actuators 510-1, 510-2, 510-3, 510-4 extend
through the opening 508. Each of the linear actuators 510-1, 510-2,
510-3, 510-4 may be secured to the second central structural member
506, e.g., using threaded fasteners inserted into openings 509-1,
509-2 that are defined within the plane of the second central
structural member 506. In some embodiments, each of the linear
actuators 510-1, 510-2, 510-3, 510-4 is rotatable about a rotation
axis, e.g., rotatable about respective shanks of the threaded
fasteners.
Each of the linear actuators 510-1, 510-2, 510-3, 510-4 connects
with the linkage system 175 at a respective first end. The linkage
system 175 connects each of the linear actuators 510-1, 510-2,
510-3, 510-4 with the interface system 110 at a respective base
513-1, 513-2, 513-3, 513-4 disposed at a top surface of the
mounting plate 170.
A respective input port 511-1, 511-2, 511-3, 511-4 is arranged at a
second end of each of the linear actuators 510-1, 510-2, 510-3,
510-4 that is opposite the first end. Each of the linear actuators
510-1, 510-2, 510-3, 510-4 has a respective exhaust port 512-1,
512-2, 512-3, 512-4 that may limit the travel of the respective
linear actuator. For example, compressed gas applied at the input
port 511-1 causes the linear actuator 510-1 to extend. Extending
the linear actuator 510-1 applies a force through the linkage
system 175 to the interface system 110 at the base 513-1. As the
linear actuator 510-1 extends beyond a threshold length, the
exhaust port 512-1 becomes communicatively coupled with the input
port 511-1 and a portion of the compressed gas exits through the
exhaust port 512-1, preventing the linear actuator 510-1 from
extending further. In some embodiments, the exhaust ports 512-1,
512-2, 512-3, 512-4 may be effectively stopped (e.g., mechanically
plugged, a compressed gas applied with a similar pressure to that
of the input ports 511-1, 511-2, 511-3, 511-4, and so forth), which
allows the linear actuators 510-1, 510-2, 510-3, 510-4 to extend
further.
Diagram 515 of FIG. 5B is a side view of the end effector with the
mounting plate 170 in an undeformed state. A first link 525 is
connected with a first end 520 of the linear actuator 510-3 at a
first joint J1. The first joint J1 is at a first radial distance
d.sub.1 from the central axis C. As shown, the first link 525
comprises a first link component 530 and a second link component
535 that is rotatable relative to the first link component.
Alternate implementations may include a monolithic first link
525.
The first link 525 is further connected with the central structural
member 505 via a second joint J2. The second joint J2 is at a
second radial distance d.sub.2 that is less than the first radial
distance d.sub.1. As shown, the first link 525 connects directly
with the central structural member 505. More specifically, the
first link component 530 connects the end 520 of the linear
actuator 510-3 with the central structural member 505, and the
second link component 535 rotatably connects the first link
component 530 with a second link 540. As shown in FIG. 5D, the
first link component 530 is rotatable relative to the central
structural member 505 about a rotation axis 541, and the second
link component 535 is rotatable relative to the first link
component 530 about a rotation axis 544. Alternate implementations
may have one or more intermediate components between the first link
525 and the central structural member 505.
Returning to FIG. 5B, the second link 540 is connected with the
first link 525 at a third joint J3. The third joint J3 is at a
third radial distance d.sub.3 that is greater than the first radial
distance d.sub.1. The second link 540 is further connected to a
lateral portion of the mounting plate 170 at a fourth joint J4 at
the base 513-3. The fourth joint J4 is at a fourth radial distance
d.sub.4 that is greater than the third radial distance d.sub.3.
Diagram 545 of FIG. 5C is a bottom perspective view of the end
effector. As shown, the pliable body member 125 is attached to a
flexible backing plate that is attached to the mounting plate 170
(e.g., via adhesive layer, glue, and/or fabric). In other
implementations the pliable body member 125 may be attached
directly to the mounting plate 170.
A threaded pipe 550 connects to the central structural member 505
and extends through the mounting plate 170 and backing plate (if
present) into the inner recess 135. A washer 560 is arranged around
the threaded pipe 550, and a nut 555 engages with the threaded pipe
550 to removably secure the backing plate and/or mounting plate 170
to the central structural member 505. The threaded pipe 550 defines
an opening 565 which allows a vacuum port to be in fluid
communication with the inner recess 135.
Diagram 570 of FIG. 5D provides an exploded view of the first link
525. The central structural member 505 defines openings 571 that
are dimensioned and arranged to receive a pin 572. The pin 572 may
contact the central structural member 505 directly, or may contact
intermediate spacer(s) (e.g., flanged bushings). The pin 572 also
extends through an opening 542 of the first link component 530,
forming the joint J2 in which the rotation axis is a longitudinal
axis 541 of the pin 572.
An opening 573 extends through the second link component 535 and is
dimensioned and arranged to receive a pin 574. The pin 574 may
contact the second link component 535 directly, or may contact
intermediate spacer(s). The pin 574 also extends into an opening
543 of the first link component 530, forming a joint J5 permitting
rotation of the second link component 535 relative to the first
link component 530. The rotation axis of the joint J5 is a
longitudinal axis 541 of the pin 572.
Diagram 575 of FIG. 5E is a side perspective view of the end
effector. Notably, the exhaust ports 512-1, 512-2, 512-3 are
depicted in the diagram 575 as being distally arranged relative to
the second central structural member 506, instead of being
proximally arranged as in FIG. 5A.
A third central structural member 576 is connected with to the
second central structural member 506, e.g., via threaded fasteners.
As shown, the third central structural member 576 and the second
central structural member 506 are directly contacting. An opening
formed through the third central structural member 576 is
dimensioned and arranged to permit rigid and/or flexible tubing to
pass through the third central structural member 576 and the second
central structural member 506, enabling fluid communication between
a vacuum source and the inner recess 135 of the pliable body member
125.
A fourth central structural member 577 is spaced apart from and
connected with the third central structural member 576. As shown,
rods 579-1, 579-2 extend between the third central structural
member 576 and the fourth central structural member 577. The rods
579-1, 579-2 have longitudinal axes that are parallel to the
central axis of the end effector. Springs 580-1, 580-2 are arranged
around respective rods 579-1, 579-2 and contact the third central
structural member 576 and the fourth central structural member
577.
Threaded fasteners and/or washers connected with the respective
rods 579-1, 579-2 may be used to maintain the third central
structural member 576 and the fourth central structural member 577
at a first distance from each other. When at the first distance,
the springs 580-1, 580-2 exert a first spring force on the third
central structural member 576 and the fourth central structural
member 577. A threaded fastener 581 and washer 582 contact the
fourth central structural member 577 to retain the third central
structural member 576 and the fourth central structural member 577
at the first distance.
In some embodiments, the rods 579-1, 579-2 extend through
respective openings in the fourth central structural member 577,
and are slidingly coupled with the sidewall(s) defining the
openings. Responsive to a force applied at the distal end of the
end effector (e.g., when an item is contacted with the sealing
surface 140), the third central structural member 576 displaces in
the proximal direction. This displacement causes the rods 579-1,
579-2 to slide in the proximal direction (e.g., such that the
threaded fastener 581 and/or the washer 582 are not contacting the
fourth central structural member 577), and the springs 580-1, 580-2
compress and exert a second spring force greater than the first
spring force. In this way, the end effector provides compliance in
the vertical direction in addition to any compliance provided by
the pliable body member 125. The additional compliance may allow
the end effector to form an improved seal with the item.
As discussed above, at least one component of the linkage system
175 may be rotatable, enabling the mounting plate 170 to rotate
about the central axis of the end effector. In some embodiments,
the assembly of the second central structural member 506 and the
third central structural member 576 is rotatable, which further
enables the mounting plate 170 to rotate. In some embodiments,
projecting members 578-1, 578-2, 578-3 extend from the surface of
the third central structural member 576 in the proximal direction.
The projecting members 578-1, 578-2, 578-3 may be connected with
the third central structural member 576 using threaded fasteners.
In some embodiments, the length of the projecting members 578-1,
578-2, 578-3 is greater than the first distance between the third
central structural member 576 and the fourth central structural
member 577. In some embodiments, a plurality of grooves are defined
by a perimeter of the fourth central structural member 577, and
each projecting member 578-1, 578-2, 578-3 extends through a
respective groove. In this way, the grooves and the projecting
members 578-1, 578-2, 578-3 may act as mechanical stops, limiting
the rotation of the assembly of the second central structural
member 506 and the third central structural member 576.
FIGS. 6A, 6B illustrate an exemplary sequence of prehending an item
using an end effector, according to various embodiments. Although
diagrams 600, 625 depict portions of the linkage system 175 of
FIGS. 5A-5E, the principles may be applied to other implementations
of the linkage system 175, such as those of FIGS. 8A-8D discussed
below.
As discussed above, the diagram 500 of FIG. 5B represents a state
of the end effector in which the mounting plate 170 is in an
undeformed state. In diagram 600 of FIG. 6A, the mounting plate 170
is in a first deformed state. In diagram 625 of FIG. 6B, the
mounting plate 170 is in a second deformed state in which the end
effector, through the mounting plate 170 and the pliable body
member 125, applies impactive forces 625-1, 625-2 to an item 615
(as shown, along the spine of a book).
The diagrams 600, 625 show two linkages 605-1, 605-2 of the linkage
system, corresponding to a pair of opposing linear actuators within
a first plane. As the actuators extend (as shown, generally in the
downward direction), the end 520 of each linkage 605-1, 605-2 moves
in the downward direction.
The downward motion of the end 520 applies a first force to the
first joint J1, which causes the first link 525 to rotate about the
second joint J2 that connects the respective linkage 605-1, 605-2
to a central structural member (represented as outline 610).
Assuming the second joints J2 are symmetrically arranged around the
center axis of the end effector, the distance between the second
joints J2 is 2d.sub.2.
Rotating the first link 525 causes a second force to be applied to
the third joint J3 connecting the first link 525 to the second link
540. Applying the second force to the third joint J3 causes a third
force to be applied to the fourth joint J4 connecting the second
link 540 with a base 513 arranged at a lateral portion of the
mounting plate 170, deforming the mounting plate 170 and altering a
geometry of the sealing surface 140.
In some embodiments, the first deformed state shown in diagram 600
represents a pre-shaping of the pliable body member 125 to cause
the sealing surface 140 to more closely match a geometry of the
item 615. When an astrictive force 620 is applied to the inner
recess, a better quality seal may be formed with the pre-shaped
pliable body member 125 than if the pliable body member 125 were in
an undeformed state.
In the diagram 625, the actuators extend further in the downward
direction, causing the mounting plate 170 to deform further. As
shown, the end effector through the mounting plate 170 and the
pliable body member 125, applies the impactive forces 625-1, 625-2
to the item 615, which may be in combination with application of
the astrictive force 620. In alternate implementations, the end
effector may apply the impactive forces 625-1, 625-2 through the
mounting plate 170.
FIGS. 7A-7C are bottom views illustrating altering a geometry of a
sealing surface by deforming a deformable plate, according to
various embodiments. The features illustrated in diagrams 700, 720,
740 may be used in conjunction with other embodiments, such as
using one or more pairs of opposing linear actuators (through
respective linkages) to deform the deformable plate.
In the diagram 700, the pliable body member 125 is in an undeformed
state and presents a substantially circular suction area 705. The
pliable body member 125 defines a plurality of features 710
arranged around the inner recess 135, which may improve the
controllability and/or the reproducibility of deforming the pliable
body member 125. Although depicted as bumps projecting into the
inner recess 135, other types of features 710 are also
contemplated. Some alternate examples of the features 710 include
gaps extending partly or fully through the pliable body member 125
along the bottom surface of the pliable body member 125, hole(s)
extending into the pliable body member 125 from the bottom surface,
and so forth. For the various examples of the features 710, the
additional or removal of material of the pliable body member 125
encourages deformation of the pliable body member 125 in a
controlled way.
In the diagram 720, the deformable plate is deformed by forces
applied along a first dimension 730 (e.g., by a first pair of
opposing linear actuators), such the pliable body member 125 is in
a deformed state and presents a substantially oval (or elliptical)
suction area 725. The elongated nature of the oval suction area 725
may be better suited for suctioning elongated items, such as a
spine of a book. In the diagram 740, the deformable plate is
deformed by forces applied along the first dimension 730 and a
second dimension 735 (e.g., by a second pair of opposing linear
actuators), such the pliable body member 125 is in a deformed state
and presents a substantially square suction area 745. The smaller
size of the square suction area 745 may be better suited for
selectively suctioning smaller items.
FIGS. 8A-8C are views of an end effector having another exemplary
implementation of the linkage system 175, according to various
embodiments. The features illustrated in diagrams 800, 815, 845 may
be used in conjunction with other embodiments discussed herein.
Diagram 800 of FIG. 8A is an isometric view of the end effector,
which comprises the linkage system 175 between a plurality of
linear actuators 810-1, 810-2, 810-3, 810-4 and the interface
system 110. The end effector further comprises a central structural
member 805, which connects with the linkage system 175 via at least
one joint. In some embodiments, at least one component of the
linkage system 175 is rotatable about a rotation axis, which causes
the mounting plate 170 to rotate about the central axis C of the
end effector. In some cases, the rotation of the mounting plate 170
also occurs within the plane of the mounting plate 170. As shown in
the diagram 815 of FIG. 8B, an intermediate member 830 is
rotatable.
The end effector further comprises a second central structural
member 806 spaced apart from, and rigidly connected with, the
central structural member 805. The second central structural member
806 is generally disk-shaped with a plurality of openings 807-1,
807-2, 807-3, 807-4 extending therethrough. The second central
structural member 806 may further define an opening permitting
fluid communication through the second central structural member
806. Each of the plurality of linear actuators 810-1, 810-2, 810-3,
810-4 connects with the linkage system 175 at a first end and
extends through a respective one of the openings 807-1, 807-2,
807-3, 807-4. A respective input port 808-1, 808-2, 808-3, 808-4 is
arranged at a second end of each of the linear actuators 810-1,
810-2, 810-3, 810-4 that is opposite the first end. For example,
compressed gas applied at the input port 808-1 causes the linear
actuator 810-1 to extend. A vacuum port 809 is arranged around the
central axis C and is connected with the second central structural
member 806. Rigid tubing is arranged between the central structural
member 805 and the second central structural member 806 and enables
fluid communication between the vacuum port 809 and the inner
recess 135 of the pliable body member 125.
The diagram 815 is a side view of the end effector with the
mounting plate 170 in an undeformed state. A first link 820 is
connected with an end (not shown) of the linear actuator 810-2 at a
first joint J1. The first joint J1 is at a first radial distance
d.sub.1 from the central axis C. The first link 820 is further
connected with the central structural member 805 via a second joint
J2. The second joint J2 is at a second radial distance d.sub.2 that
is less than the first radial distance d.sub.1. As shown, the first
link 820 connects indirectly with the central structural member 805
via the intermediate member 830.
A second link 825 is connected with the first link 820 at a third
joint J3. The third joint J3 is at a third radial distance d.sub.3
that is greater than the first radial distance d.sub.1. The second
link 540 is further connected to a lateral portion of the mounting
plate 170 at a fourth joint J4 at the base 513-2. The fourth joint
J4 is at a fourth radial distance d.sub.4 that is greater than the
third radial distance d.sub.3.
The intermediate member 830 further connects with an exterior of
the linear actuator 810-2 via a fifth joint J5. The fifth joint J5
is at a fifth radial distance greater than the second radial
distance d.sub.2. In some embodiments, the fifth joint J5 is at a
sleeve 835 arranged around the linear actuator 810-2. The sleeve
835 is configured to move along a length of the linear actuator
810-2 and/or to rotate about the linear actuator 810-2, e.g., as
the intermediate member 830 is rotated.
The intermediate member 830 further connects with the central
structural member 805 via a sixth joint J6. As shown, the sixth
joint J6 has a radial distance close to the second radial distance
d.sub.2. In some embodiments, the rotation axis about which the at
least one component of the linkage system 175 (e.g., the
intermediate member 830) rotates is substantially parallel to the
central axis C of the end effector.
Diagram 845 provides a partially exploded view of the end effector.
The intermediate member 830 defines an opening 850 through which
the linear actuator 810-1 passes. The opening 850 limits a range of
motion of the linear actuator 810-1 when the intermediate member
830 is rotated about the rotation axis. In some embodiments, the
central structural member 805 comprises one or more stop features
840 that limit a range of rotation of the intermediate member 830
about the rotation axis.
The central structural member 805 comprising a central tube and
projecting portions 865 that are each arranged to receive a pin
864. The pin 864 may contact the projecting portion 865 directly,
or may contact intermediate spacer(s). The pin 864 also extends
into openings 863 of the intermediate member 830, forming the joint
J6 in which the rotation axis is a longitudinal axis 866 of the pin
864.
Openings 853 extend through the intermediate member 830 near a
proximal end, and are dimensioned and arranged to receive a pin
852. The pin 852 may contact the intermediate member 830 directly,
or may contact intermediate spacer(s). The pin 852 also extends
through an opening 851 of the sleeve 835, forming the joint J5 in
which the rotation axis is a longitudinal axis 854 of the pin
852.
Openings 855 extend through the intermediate member 830 near a
distal end, and are dimensioned and arranged to receive a pin 856.
The pin 856 may contact the intermediate member 830 directly, or
may contact intermediate spacer(s). The pin 856 also extends
through an opening 858 of the first link 820, forming the joint J2
in which the rotation axis is a longitudinal axis 857 of the pin
856.
Openings 859 extend through the first link 820 and are dimensioned
and arranged to receive a pin 860. The pin 860 may contact the
first link 820 directly, or may contact intermediate spacer(s). The
pin 860 also extends through an opening 862 of the second link 825,
forming the joint J3 in which the rotation axis is a longitudinal
axis 861 of the pin 860.
FIGS. 9A-9D are views of an exemplary end effector having a
rotatable structural assembly, according to various embodiments.
The features illustrated in diagrams 900, 930, 990, 995 may be used
in conjunction with other embodiments discussed herein, e.g., using
one of the implementations of the linkage system depicted in FIGS.
5A-5E and FIGS. 8A-8C.
Diagram 900 of FIG. 9A is an isometric view of the end effector,
which comprises the linkage system 175 between a plurality of
linear actuators and the interface system 110. The end effector
further comprises a circuit board 911 arranged between sidewalls
910-1, 910-2 and a motor 920 arranged between, and mounted to, the
sidewalls 910-1, 910-2. The circuit board 911 comprises circuitry
that controls some or all of the functionality of the end effector.
For example, the circuit board 911 may control operation of the
motor 920 and/or the actuators connected to the linkage system
175.
The sidewalls 910-1, 910-2 are connected with a base 925. Although
not illustrated, a housing may enclose the motor 920 and the
sidewalls 910-1, 910-2, as well as other components of the end
effector. The motor 920, which in some embodiments is connected
with a belt drive, is configured to control an orientation of the
end effector, e.g., to more closely match an orientation and/or a
surface geometry of an item.
A tube 905 is mounted to a lateral surface of the sidewall 910-1
and extends along a longitudinal axis of the sidewall 910-1. In
some embodiments, the tube 905 is in fluid communication with a
vacuum source at a proximal end of the end effector, and with the
inner recess of the pliable body member 125 at a distal end of the
end effector. In some embodiments, the tube 905 connects with a
tube 915 that is arranged laterally to, and is partly overlapping
with, the belt drive. In some embodiments, the tube 915 is
connected to an opening extending through a sprocket of the belt
drive, and the inner recess and/or plurality of actuators are in
fluid communication through the opening.
In diagrams 930, 990 of FIGS. 9B and 9C, a structural assembly 956
of the end effector comprises a central structural member 960 to
which the linkage system 175 is connected, and a second central
structural member 970 spaced apart from, and rigidly connected
with, the central structural member 960. Each linear actuator of
the plurality of linear actuators 510-1, 510-2, 510-3, 510-4 is
connected with the second central structural member 970 at a
respective second end 974-1 that is opposite the end 972-1
connected with the linkage system 175. The structural assembly 956
further comprises a third central structural member 965 connected
with one or both of the central structural member 960 and the
second central structural member 970.
The motor 920 is connected with a first sprocket 940 through an
opening 935 of the sidewall 910-1, and a toothed belt 950 connects
the first sprocket 940 with a second socket 945. The second socket
945 connects with the third central structural member 965 to enable
rotation of the structural assembly 956 about a second rotation
axis 958 extending through the third central structural member 965.
In some embodiments, a vacuum port is in fluid communication with
the inner recess of the pliable body member 125 through an opening
955 formed in the second socket, and through an opening 966 of the
third central structural member 965.
Diagram 995 of FIG. 9D provides a partially exploded view of the
structural assembly 956. The second central structural member 970
is rigidly connected with the central structural member 960 by a
tube 988 having an opening 989 extending therethrough, enabling
fluid communication between the opening 966 of the third central
structural member 965 and an opening 961 of the central structural
member 960. In some embodiments, flexible tubing connects to a
plurality of ports 967 of the third central structural member 965,
enabling fluid communication between one or more compressed gas
sources and the actuators through the third central structural
member 965. The second central structural member 970 is further
connected with the central structural member 960 by a compliance
and return assembly 976 that enables motion of the central
structural member 960 and the third central structural member 965
relative to the second central structural member 970, providing an
improved compliance of the end effector in the vertical direction.
The compliance and return assembly 976 comprises, for opposing
sides of the central structural member 960 and the second central
structural member 970, a cage 980 included in the third central
structural member 965, tubular members 982-1, 982-2 (e.g.,
bushings) retained in the cage 980, a spring 984 arranged in the
openings of the tubular members 982-1, 982-2 and compressed
therebetween, and a rod 978 extending through the cage 980 and the
spring 984. A spacer 986 is arranged between the cage 980 and the
central structural member 960. The rod 978 is connected to the
second central structural member 970 and to the central structural
member 960 using, e.g., threaded fasteners.
The descriptions of the various embodiments of the present
invention have been presented for purposes of illustration, but are
not intended to be exhaustive or limited to the embodiments
disclosed. Many modifications and variations will be apparent to
those of ordinary skill in the art without departing from the scope
and spirit of the described embodiments. The terminology used
herein was chosen to best explain the principles of the
embodiments, the practical application or technical improvement
over technologies found in the marketplace, or to enable others of
ordinary skill in the art to understand the embodiments disclosed
herein.
In the preceding, reference is made to embodiments presented in
this disclosure. However, the scope of the present disclosure is
not limited to specific described embodiments. Instead, any
combination of the features and elements described herein, whether
related to different embodiments or not, is contemplated to
implement and practice contemplated embodiments. Furthermore,
although embodiments disclosed herein may achieve advantages over
other possible solutions or over the prior art, whether or not a
particular advantage is achieved by a given embodiment is not
limiting of the scope of the present disclosure. Thus, the aspects,
features, embodiments and advantages described herein are merely
illustrative and are not considered elements or limitations of the
appended claims except where explicitly recited in a claim(s).
Likewise, reference to "the invention" shall not be construed as a
generalization of any inventive subject matter disclosed herein and
shall not be considered to be an element or limitation of the
appended claims except where explicitly recited in a claim(s).
Aspects of the present invention may take the form of an entirely
hardware embodiment, an entirely software embodiment (including
firmware, resident software, micro-code, etc.) or an embodiment
combining software and hardware aspects that may all generally be
referred to herein as a "circuit," "module" or "system."
The present invention may be a system, a method, and/or a computer
program product. The computer program product may include a
computer readable storage medium (or media) having computer
readable program instructions thereon for causing a processor to
carry out aspects of the present invention.
The computer readable storage medium can be a tangible device that
can retain and store instructions for use by an instruction
execution device. The computer readable storage medium may be, for
example, but is not limited to, an electronic storage device, a
magnetic storage device, an optical storage device, an
electromagnetic storage device, a semiconductor storage device, or
any suitable combination of the foregoing. A non-exhaustive list of
more specific examples of the computer readable storage medium
includes the following: a portable computer diskette, a hard disk,
a random access memory (RAM), a read-only memory (ROM), an erasable
programmable read-only memory (EPROM or Flash memory), a static
random access memory (SRAM), a portable compact disc read-only
memory (CD-ROM), a digital versatile disk (DVD), a memory stick,
and any suitable combination of the foregoing. A computer readable
storage medium, as used herein, is not to be construed as being
transitory signals per se, such as radio waves or other freely
propagating electromagnetic waves, electromagnetic waves
propagating through a waveguide or other transmission media (e.g.,
light pulses passing through a fiber-optic cable), or electrical
signals transmitted through a wire.
Computer readable program instructions described herein can be
downloaded to respective computing/processing devices from a
computer readable storage medium or to an external computer or
external storage device via a network, for example, the Internet, a
local area network, a wide area network and/or a wireless network.
The network may comprise copper transmission cables, optical
transmission fibers, wireless transmission, routers, firewalls,
switches, gateway computers and/or edge servers. A network adapter
card or network interface in each computing/processing device
receives computer readable program instructions from the network
and forwards the computer readable program instructions for storage
in a computer readable storage medium within the respective
computing/processing device.
Computer readable program instructions for carrying out operations
of the present invention may be assembler instructions,
instruction-set-architecture (ISA) instructions, machine
instructions, machine dependent instructions, microcode, firmware
instructions, state-setting data, or either source code or object
code written in any combination of one or more programming
languages, including an object oriented programming language such
as Smalltalk, C++ or the like, and conventional procedural
programming languages, such as the "C" programming language or
similar programming languages. The computer readable program
instructions may execute entirely on the user's computer, partly on
the user's computer, as a stand-alone software package, partly on
the user's computer and partly on a remote computer or entirely on
the remote computer or server. In the latter scenario, the remote
computer may be connected to the user's computer through any type
of network, including a local area network (LAN) or a wide area
network (WAN), or the connection may be made to an external
computer (for example, through the Internet using an Internet
Service Provider). In some embodiments, electronic circuitry
including, for example, programmable logic circuitry,
field-programmable gate arrays (FPGA), or programmable logic arrays
(PLA) may execute the computer readable program instructions by
utilizing state information of the computer readable program
instructions to personalize the electronic circuitry, in order to
perform aspects of the present invention.
Aspects of the present invention are described herein with
reference to flowchart illustrations and/or block diagrams of
methods, apparatus (systems), and computer program products
according to embodiments of the invention. It will be understood
that each block of the flowchart illustrations and/or block
diagrams, and combinations of blocks in the flowchart illustrations
and/or block diagrams, can be implemented by computer readable
program instructions.
These computer readable program instructions may be provided to a
processor of a general purpose computer, special purpose computer,
or other programmable data processing apparatus to produce a
machine, such that the instructions, which execute via the
processor of the computer or other programmable data processing
apparatus, create means for implementing the functions/acts
specified in the flowchart and/or block diagram block or blocks.
These computer readable program instructions may also be stored in
a computer readable storage medium that can direct a computer, a
programmable data processing apparatus, and/or other devices to
function in a particular manner, such that the computer readable
storage medium having instructions stored therein comprises an
article of manufacture including instructions which implement
aspects of the function/act specified in the flowchart and/or block
diagram block or blocks.
The computer readable program instructions may also be loaded onto
a computer, other programmable data processing apparatus, or other
device to cause a series of operational steps to be performed on
the computer, other programmable apparatus or other device to
produce a computer implemented process, such that the instructions
which execute on the computer, other programmable apparatus, or
other device implement the functions/acts specified in the
flowchart and/or block diagram block or blocks.
The flowchart and block diagrams in the FIGS. illustrate the
architecture, functionality, and operation of possible
implementations of systems, methods, and computer program products
according to various embodiments of the present invention. In this
regard, each block in the flowchart or block diagrams may represent
a module, segment, or portion of instructions, which comprises one
or more executable instructions for implementing the specified
logical function(s). In some alternative implementations, the
functions noted in the block may occur out of the order noted in
the FIGS. For example, two blocks shown in succession may, in fact,
be executed substantially concurrently, or the blocks may sometimes
be executed in the reverse order, depending upon the functionality
involved. It will also be noted that each block of the block
diagrams and/or flowchart illustration, and combinations of blocks
in the block diagrams and/or flowchart illustration, can be
implemented by special purpose hardware-based systems that perform
the specified functions or acts or carry out combinations of
special purpose hardware and computer instructions.
While the foregoing is directed to embodiments of the present
invention, other and further embodiments of the invention may be
devised without departing from the basic scope thereof, and the
scope thereof is determined by the claims that follow.
* * * * *